diff --git a/src/common/ui_utils/mainwindowwithtray.cpp b/src/common/ui_utils/mainwindowwithtray.cpp
index dbac8f8..7c0f575 100644
--- a/src/common/ui_utils/mainwindowwithtray.cpp
+++ b/src/common/ui_utils/mainwindowwithtray.cpp
@@ -59,8 +59,8 @@ void MainWindowWithTray::trayAction(QSystemTrayIcon::ActivationReason reason)
 void MainWindowWithTray::closeApp()
 {
     m_isExiting = true;
-    qApp->closeAllWindows();
-    qApp->exit(0);
+    QApplication::closeAllWindows();
+    QCoreApplication::exit(0);
 }
 
 void MainWindowWithTray::setVisible(bool visible)
@@ -104,7 +104,7 @@ void MainWindowWithTray::showHideNotify() {}
 
 void MainWindowWithTray::createTrayMenu(QIcon const& icon, utilities::Tr::Translation const& projFullNameTr)
 {
-    qApp->setWindowIcon(icon);
+    QApplication::setWindowIcon(icon);
 #if !defined(Q_OS_MAC)
     m_tray = new QSystemTrayIcon(this);
     utilities::Tr::SetTr(m_tray, &QSystemTrayIcon::setToolTip, projFullNameTr);
@@ -136,7 +136,7 @@ QAction* MainWindowWithTray::addTrayMenuItem(TrayMenu::ItemType itemType)
     case TrayMenu::Show:
     {
         action = createAction("actionShow", appShowTr, QKeySequence::UnknownKey, SLOT(restore()));
-        action->setIcon(qApp->windowIcon());
+        action->setIcon(QApplication::windowIcon());
         action->setIconVisibleInMenu(true);
         m_tray->contextMenu()->addAction(action);
     }
diff --git a/src/common/utilities/associate_app_win.cpp b/src/common/utilities/associate_app_win.cpp
index 984fbfa..60b5240 100644
--- a/src/common/utilities/associate_app_win.cpp
+++ b/src/common/utilities/associate_app_win.cpp
@@ -12,7 +12,7 @@ const auto torrentClassName = QStringLiteral(PROJECT_NAME ".torrent");
 
 void setClassesToSelf(QSettings& settingRoot)
 {
-    QString appPath = QDir::toNativeSeparators(qApp->applicationFilePath());
+    QString appPath = QDir::toNativeSeparators(QCoreApplication::applicationFilePath());
     settingRoot.setValue(".", torrentClassName);
 
     settingRoot.beginGroup("DefaultIcon");
@@ -34,7 +34,7 @@ void associateApp(QString const& ext, WId parent = NULL)
     const bool isChangeNeeded =
         QSettings("HKEY_CLASSES_ROOT\\" + torrentClassName, QSettings::NativeFormat).value(".") != PROJECT_FULLNAME ||
         QSettings("HKEY_CLASSES_ROOT\\" + ext, QSettings::NativeFormat).value(".") != torrentClassName ||
-        QSettings("HKEY_CLASSES_ROOT\\" + torrentClassName + "\\shell\\open\\command", QSettings::NativeFormat).value(".") != QString("\"%1\" \"%2\"").arg(QDir::toNativeSeparators(qApp->applicationFilePath()), "%1");
+        QSettings("HKEY_CLASSES_ROOT\\" + torrentClassName + "\\shell\\open\\command", QSettings::NativeFormat).value(".") != QString("\"%1\" \"%2\"").arg(QDir::toNativeSeparators(QCoreApplication::applicationFilePath()), "%1");
 
     if (isChangeNeeded)
     {
@@ -75,7 +75,7 @@ bool utilities::isDefaultTorrentApp()
     const bool isSelf =
         QSettings("HKEY_CLASSES_ROOT\\Magnet", QSettings::NativeFormat).value(".") == torrentClassName &&
         QSettings("HKEY_CLASSES_ROOT\\.torrent", QSettings::NativeFormat).value(".") == torrentClassName &&
-        QSettings("HKEY_CLASSES_ROOT\\" + torrentClassName + "\\shell\\open\\command", QSettings::NativeFormat).value(".") == QString("\"%1\" \"%2\"").arg(QDir::toNativeSeparators(qApp->applicationFilePath()), "%1") &&
+        QSettings("HKEY_CLASSES_ROOT\\" + torrentClassName + "\\shell\\open\\command", QSettings::NativeFormat).value(".") == QString("\"%1\" \"%2\"").arg(QDir::toNativeSeparators(QCoreApplication::applicationFilePath()), "%1") &&
         QSettings("HKEY_CURRENT_USER\\Software\\Microsoft\\Windows\\CurrentVersion\\Explorer\\FileExts\\.torrent\\UserChoice", QSettings::NativeFormat).value("ProgId") == torrentClassName;
 
     return isSelf;
diff --git a/src/common/utilities/filesystem_utils.cpp b/src/common/utilities/filesystem_utils.cpp
index 5802936..10fa381 100644
--- a/src/common/utilities/filesystem_utils.cpp
+++ b/src/common/utilities/filesystem_utils.cpp
@@ -1,9 +1,11 @@
 #include "filesystem_utils.h"
 
+#include <QApplication>
 #include <QFileInfo>
 #include <QFile>
 #include <QDir>
 #include <QDebug>
+#include <QSettings>
 #include <QThread>
 #include <QProcess>
 #include <QNetworkReply>
@@ -24,6 +26,9 @@ typedef HRESULT(STDAPICALLTYPE* GetPathFunc)(REFKNOWNFOLDERID, DWORD, HANDLE, PW
 
 namespace {
 
+const char PORTABLE_MODE_FILE[]        =    "portable";
+const char DOWNLOADS_FOLDER_NAME[]     =    "downloads";
+
 #ifdef Q_OS_WIN32
 const char EXPLORER_LABEL[]            =    "explorer";
 #elif defined(Q_OS_MAC)
@@ -153,6 +158,27 @@ bool MoveToTrashImpl(const QString& file)
 }
 #endif //Q_OS_MAC
 
+QString StringOrEmpty(const QStringList& list)
+{
+    return list.empty() ? QString() : list.at(0);
+}
+
+QString GetOrganizationName()
+{
+    return
+#ifdef Q_OS_MAC
+    QCoreApplication::organizationDomain().isEmpty()
+        ? QCoreApplication::organizationName()
+        : QCoreApplication::organizationDomain()
+#else
+    QCoreApplication::organizationName().isEmpty()
+        ? QCoreApplication::organizationDomain()
+        : QCoreApplication::organizationName()
+#endif
+    ;
+}
+
+
 } // namespace
 
 
@@ -239,22 +265,30 @@ QString GetFileName(const QString& full_path)
     return (file_name.isEmpty()) ? full_path : file_name;
 }
 
+bool IsPortableMode()
+{
+    static const bool isPortableMode = QFileInfo::exists(
+        QCoreApplication::applicationDirPath() + QDir::separator() + PORTABLE_MODE_FILE);
+    return isPortableMode;
+}
+
 QString getPathForDownloadFolder()
 {
-    QStringList paths = QStandardPaths::standardLocations(QStandardPaths::DownloadLocation);
-    QString startPath = !paths.empty() ? paths.at(0) : QString();
-    return startPath;
+    return IsPortableMode()
+        ? PrepareCacheFolder(DOWNLOADS_FOLDER_NAME)
+        : StringOrEmpty(QStandardPaths::standardLocations(QStandardPaths::DownloadLocation));
 }
 
 
 QString PrepareCacheFolder(const QString& subdir)
 {
-    QStringList paths = QStandardPaths::standardLocations(QStandardPaths::DataLocation);
-    QString path = !paths.isEmpty() ? paths.at(0) : QString();
+    QString path = IsPortableMode()
+        ? QCoreApplication::applicationDirPath()
+        : StringOrEmpty(QStandardPaths::standardLocations(QStandardPaths::DataLocation));
 
-    if (!subdir.isEmpty())
+    if (!subdir.isEmpty() || IsPortableMode()) // indirect top level portable stuff like settings do
     {
-        path += QDir::separator() + subdir;
+        path += QDir::separator() + (subdir.isEmpty()? GetOrganizationName() : subdir);
     }
     Q_ASSERT(!path.isEmpty());
 
diff --git a/src/common/utilities/filesystem_utils.h b/src/common/utilities/filesystem_utils.h
index 7dd8701..12620fd 100644
--- a/src/common/utilities/filesystem_utils.h
+++ b/src/common/utilities/filesystem_utils.h
@@ -21,6 +21,8 @@ void SelectFile(const QString& fileName, const QString& defFolderName);
 QString GetFileName(QNetworkReply* reply);
 QString GetFileName(const QString& full_path);
 
+bool IsPortableMode();
+
 // Parameter: const QString & subdir - subdir to create;  Returns:  QString - directory name with ending slash
 QString PrepareCacheFolder(const QString& subdir = QString());
 
diff --git a/src/common/utilities/translatable.cpp b/src/common/utilities/translatable.cpp
index c8e5728..f21111a 100644
--- a/src/common/utilities/translatable.cpp
+++ b/src/common/utilities/translatable.cpp
@@ -88,7 +88,7 @@ void Translatable::retranslateApp(const QString& locale)
 {
     if (translator_)
     {
-        qApp->removeTranslator(translator_);
+        QCoreApplication::removeTranslator(translator_);
         translator_->deleteLater();
     }
     translator_ = new QTranslator(qApp);
@@ -96,7 +96,7 @@ void Translatable::retranslateApp(const QString& locale)
     QString filename = translationFilePrefix + locale;
     if (translator_->load(filename, getTranslationsFolder()))
     {
-        qApp->installTranslator(translator_);
+        QCoreApplication::installTranslator(translator_);
     }
 
     Tr::RetranslateAll(qApp);
diff --git a/src/common/utilities/utils.cpp b/src/common/utilities/utils.cpp
index eded4b2..6ddc128 100644
--- a/src/common/utilities/utils.cpp
+++ b/src/common/utilities/utils.cpp
@@ -349,8 +349,8 @@ bool isAdminRights()
 
 void runWithPrivileges(const wchar_t* arg, WId parent)
 {
-    const auto applicationFilePath = qApp->applicationFilePath();
-    const auto applicationDirPath = qApp->applicationDirPath();
+    const auto applicationFilePath = QCoreApplication::applicationFilePath();
+    const auto applicationDirPath = QCoreApplication::applicationDirPath();
 
     SHELLEXECUTEINFOW shex =
     {
diff --git a/src/gui/mainwindow.cpp b/src/gui/mainwindow.cpp
index 267f654..324b3a6 100644
--- a/src/gui/mainwindow.cpp
+++ b/src/gui/mainwindow.cpp
@@ -72,7 +72,7 @@ MainWindow::MainWindow()
       m_dlManager(nullptr)
       , isAutorun(false)
 {
-    qApp->setWindowIcon(QIcon(PROJECT_ICON));
+    QApplication::setWindowIcon(QIcon(PROJECT_ICON));
 
     ui->setupUi(this);
 
@@ -153,7 +153,7 @@ MainWindow::MainWindow()
 
     VERIFY(connect(ui->linkEdit, SIGNAL(linksAdd(bool)), ui->lblClearText, SLOT(setVisible(bool))));
     VERIFY(connect(ui->linkEdit, SIGNAL(returnPressed()), this, SLOT(on_buttonStart_clicked())));
-    VERIFY(connect(ui->lblClearText, SIGNAL(clicked()), this, SLOT(onlblClearTextCliced())));
+    VERIFY(connect(ui->lblClearText, SIGNAL(clicked()), this, SLOT(onlblClearTextClicked())));
 
     refreshButtons();
 }
@@ -211,7 +211,8 @@ void MainWindow::showMainWindowAndPerformChecks()
 
 void MainWindow::checkDefaultTorrentApplication()
 {
-    if (QSettings().value(ShowAssociateTorrentDialog, ShowAssociateTorrentDialog_Default).toBool()
+    const bool initiallyShowDialog = ShowAssociateTorrentDialog_Default && !utilities::IsPortableMode();
+    if (QSettings().value(ShowAssociateTorrentDialog, initiallyShowDialog).toBool()
         && !utilities::isDefaultTorrentApp())
     {
         QMessageBox msgBox(
@@ -318,7 +319,7 @@ void MainWindow::prepareToExit()
 #endif
 }
 
-void MainWindow::onlblClearTextCliced()
+void MainWindow::onlblClearTextClicked()
 {
     ui->linkEdit->setText(QString());
     refreshButtons();
diff --git a/src/gui/mainwindow.h b/src/gui/mainwindow.h
index e9978cd..32c070f 100644
--- a/src/gui/mainwindow.h
+++ b/src/gui/mainwindow.h
@@ -71,7 +71,7 @@ public Q_SLOTS:
     void closeApp();
     void onAboutClicked();
     void on_openTorrent_clicked();
-    void onlblClearTextCliced();
+    void onlblClearTextClicked();
 
 private Q_SLOTS:
     void prepareToExit();
diff --git a/src/gui/torrentdetailsform.cpp b/src/gui/torrentdetailsform.cpp
index 3ae85be..af1939f 100644
--- a/src/gui/torrentdetailsform.cpp
+++ b/src/gui/torrentdetailsform.cpp
@@ -202,7 +202,7 @@ template<class Val_t> bool isNotAllSkipped(std::vector<Val_t> const& priorities)
 
 void TorrentDetailsForm::accept()
 {
-    qApp->processEvents(); // must call this to stop editing operations
+    QCoreApplication::processEvents(); // must call this to stop editing operations
 
     bool isEverithingOk = true;
     if (m_torrentHandle.is_valid())
diff --git a/src/main/main.cpp b/src/main/main.cpp
index e966e21..1dd42aa 100644
--- a/src/main/main.cpp
+++ b/src/main/main.cpp
@@ -27,12 +27,26 @@ Q_IMPORT_PLUGIN(qico)
 #endif//QT_STATICPLUGINS
 
 
+// Called once QCoreApplication exists
+static void ApplicationDependentInitialization()
+{
+    if (utilities::IsPortableMode())
+    {
+        QSettings::setDefaultFormat(QSettings::IniFormat);
+        QSettings::setPath(QSettings::IniFormat, QSettings::UserScope,
+            QCoreApplication::applicationDirPath());
+    }
+
+    utilities::setWriteToLogFile(
+        QSettings().value(app_settings::LoggingEnabled, false).toBool());
+}
+
+Q_COREAPP_STARTUP_FUNCTION(ApplicationDependentInitialization)
+
 int main(int argc, char* argv[])
 {
     utilities::InitializeProjectDescription();
 
-    utilities::setWriteToLogFile(QSettings().value(app_settings::LoggingEnabled, false).toBool());
-
     // single app
     Application app(QString(PROJECT_NAME), argc, argv);